我国主要类型土壤中银的环境过程及其生态环境阈值研究

Mining activity and the wide use of Ag-containing commercial products have led to elevated concentrations of Ag in surface soils. However, the environmental behaviors of Ag and its associated ecological effects are less understood. The chemical transformation and fates of Ag ions in main types of soils in China will be investigated with the help of XANES analysis, stable isotope tracing technique, and single-particle ICP-MS together with traditional techniques. Meanwhile, the bioavailability and toxic effects of Ag in soils on plants, invertebrates and microbiota will be evaluated, and dose-effect correlations based on soil properties and Ag bioavailability will be established. Finally, the effect threshold concentrations of Ag in different types of soils will be validated by field study. Results gained in the present study would provide theoretical basis for establishing soil environmental quality criteria for Ag in China.

矿业开采及含银产品的广泛使用导致土壤中银的累积。但是目前土壤中银的环境过程和生态效应尚不清楚。结合同步辐射、同位素示踪、SP-ICP-MS等现代分析技术和传统土壤化学方法，本项目系统深入研究Ag离子在我国主要类型土壤中的化学转化过程和赋存形态；考察土壤Ag对植物、土壤动物和微生物的致毒效应，建立基于土壤性质和Ag生物有效性的剂量-效应关系；获得不同类型土壤Ag的环境质量阈值，并通过田间和野外调查进行验证，为建立我国土壤Ag的环境质量基准提供科学依据。

本项目系统研究了我国主要类型土壤中银的界面化学过程，基于同步辐射和单颗粒耦合等离子体质谱技术获取了多种类型土壤中银的化学形态转化过程，阐明了银的还原、硫化、氧化溶解以及硫化后二次释放过程及分子机制，并明确了银形态转化的关键影响因素。基于大麦根伸长试验和蚯蚓的致死和生殖毒性试验，在不同类型土壤中建立了银对大麦和蚯蚓的剂量-效应关系，建立了土壤性质与毒性阈值的回归方程，明确了影响土壤银毒性阈值的关键土壤因子。在此基础上，应用稳定同位素示踪技术深入开展了银的食物链传递与生物效应的田间试验，全面评估了银的生态环境风险。发表高质量SCI论文11篇，培养研究生4名。